Lawyers for the U.S. Justice Department oppose a request to merge their challenge to the new Arizona immigration law with a lawsuit by a police officer who also is seeking to overturn the law.

The federal lawyers oppose Phoenix police Officer David Salgado's request to consolidate the cases because they say it would prejudice or delay their challenge.

The officer's attorney had argued that the cases are virtually identical because they claim the state law is trumped by federal immigration law and because both seek to keep the state law from being enforced.

The Justice Department says it's challenging more sections of the law than Salgado and that its contention that the law is trumped by federal law differs from the officer's arguments.